2,4-Dichlorophenoxyacetic acid removal from aqueous solutions via adsorption in the presence of biological contamination

In this study, the adsorption of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), a chemical agricultural pollutant, onto granular activated carbon (GAC) was accomplished in the presence of biological contaminants in a batch and continuous system. In the batch studies, the maximum sorption capacities (mg/g) exhibited by GAC were found to be 5.9, 76.8, 124.0, 173.1, and 177.6 in the presence of Acidovorax avenae subsp. avenae LMG 17238, Gracilaria verrucosa, a group of aquarium-isolated microorganisms, Spirulina platensis, and in the absence of microorganisms, respectively. Two and three-parameter non-linear equilibrium models - Langmuir, Freundlich, Redlich-Peterson, Sips, and Toth - were applied to describe the batch sorption process. In the continuous-flow column studies, breakthrough curves were plotted as a function of influent 2,4-D concentration (50-200 mg/L), flow rate (0.2-0.4 mL/min), GAC mass (0.75-1.5 g), and microorganism load. The highest bed capacity was obtained by using 200 mg/L inlet 2,4-D concentration, 0.2 mL/min flow rate and 1.5 g GAC mass. In the presence of biological contaminants, the order of adsorption of 2,4-D in terms of the maximum adsorption capacity (mg/g) from the least to the greatest was as follows: no microorganism < S. platensis < the aquarium-isolated group of microorganisms < G. verrucosa < LMG 17238. Among the kinetic models applied to the fixed-bed column data, the Thomas and Yoon-Nelson models showed a better fit than the Bohart-Adams. © 2013 Elsevier Ltd. All rights reserved.This work has been carried out within the scope of the Research Foundation of Ege University. -

In-vitro antioxidative and antimicrobial activity of Gracilaria sp via secondary metabolites profile

WOS: 00043767410226

Adsorption of atrazine and simazine from aqueous solutions onto poly(?-caprolactone)

The biodegradable synthetic polymer poly(?-caprolactone) was investigated as a substrate for denitrification. This substrate may also act as an adsorbent for two pesticides, i.e., atrazine and simazine, from water. The equilibrium was studied at 25, 35 and 45°C. The results were correlated using the Langmuir and Freundlich adsorption models. The total capacities of the adsorbent were defined from experimental data for atrazine (10.98 mg g-1) and simazine (27.54 mg g-1). The effect of temperature on the model constants and the thermodynamics of adsorption were investigated. The evaluation of the development of adsorption was achieved by assuming a pseudo-second order chemical reaction. © 2008 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim

Potential of the bacterial strain Acidovorax avenae subsp. avenae LMG 17238 and macro algae Gracilaria verrucosa for denitrification

In this biological nitrate removal study, the performance of the bacterial strain Acidovorax avenae subsp. avenae LMG 17238 using different carbon sources such as ethanol, methanol, sodium acetate, glucose and poly(?-caprolactone) was investigated. Additionally the parameters such as an increase of nitrate concentration, carbon source amount (C/N) and dilution of a synthetic medium were studied. In laboratory conditions LMG 17238 and a mixed bacterial culture (soil suspension, wastewater treatment and macro algae Gracilaria verrucosa) have been immobilized as a comparative study to determine their efficiency in the biological denitrification of drinking water. For the continuous system as a carbon source, G. verrucosa was studied in fixed-bed columns. Various variables such as hydraulic retention time (HRT), mass amount of the substrate, and the initial nitrate concentration were investigated. A comparative study was achieved by using biodegradable poly(?-caprolactone) as a carbon source using a mixed bacterial culture (LMG 17238 and G. verrucosa) in a fixed-bed column. Also Monod type equations were used to model the denitrification kinetics. The study proves that, LMG 17238 can be successfully used with different carbon sources. G. verrucosa can be considered as a promising alternative to poly(?-caprolactone) with a maximum denitrification rate of 13.83 and 0.94mgNO3-N/Ld respectively. © 2011 Elsevier B.V.The authors would like to thank Dr. W. R. Müller, Dr. J. Mergaert and Prof. Dr. U. Obst for their support, which enabled this biological denitrification project. The authors would also like to thank A. Ata for her assistance in the preparation of this manuscript. The author B. Ovez, would like to thank DAAD for the scholarship, which enabled us to start the project work at Karlsruhe and Stuttgart Universities. This work was financed by the Research Foundation of Ege University , EBILTEM and TUBITAK . -

Toxicity determination of various phenoxyalkanoic acid herbicides using cress seed in phosphate contaminated aqueous media

WIT Transactions on Ecology and the Environment8th International Conference on Modelling, Monitoring and Management of Water Pollution, WATER POLLUTION 2006, WP06 -- 4 September 2006 through 6 September 2006 -- Bologna -- 69577In the industrial world there is growing evidence of ground water contamination. Environmentally relevant bio-tests provide information on initial levels of damage and disasters and assist in developing precautionary measures and strategies for the environment. Plant toxicity tests are not only quick and inexpensive relative to the more sophisticated chemical analyses, but also require less maintenance than other tests which use organisms. In this research, garden cress seeds (Lepidium sativum L) were exposed to different phenoxyalkanoic acid herbicides 2,4-D(2,4-dicholorophenoxy) acetic acid), 2,4-DP((RS)-2,(2,4-dichlorophenoxy) propionic acid), 2,4-DB (4-(2, 4dichlorophenoxy)butyric acid), 2,4,5-T (2,4,5-trichlorophenoxy)acetic acid), and MCPA (4-chloro-2-methylphenoxy) acetic acid) in a phosphate contaminated media for 120 h in order to determine the effect of toxicity to root growth. Each trial was duplicated for consistency of the experimental results (significance is taken as p < 0.01). As an analytical approach IC50 (50% inhibitory concentration) values of the substances were found from the graphical expressions of root length inhibitions. For the determination of the IC50 values, a non-linear regression model was applied using the least square method. The calculated IC50 values clearly represent the toxicity of the herbicides

Antimicrobial resistance of Staphylococcus aeureus to multi-heavy metal aqueous solutions

42nd Congress of the Federation-of-European-Biochemical-Societies (FEBS) on From Molecules to Cells and Back -- SEP 10-14, 2017 -- Jerusalem, ISRAELWOS: 000409918904122Federat European Biochem So